If AF447 black boxes are not found and another Airbus aircraft is lost under similar circumstances, there will be a crisis of confidence in Airbus aircraft. The financial implications of such a crisis would be much worse than the cost of this search. The sooner they find the black boxes and determine the cause, the better for Airbus and all who depend on Airbus.
BEA has a daunting job making sure that they get the best bang for the Franc.
Just my take on the situation. I know some are much more skeptical.